Ron Hardin wrote:

My general impression of modern receivers is that they're already really
sensitive. You get more signal and equally more noise from a bigger
antenna, so you're not ahead once you're above the internal noise of
the receiver, which is what is low in modern receivers and so you
don't see much advantage once you're beyond the minimum antenna.

On the other hand, you get increased intermodulation and overload
from other signals you're not meaning to listen to, and that's
something modern receivers are not designed to suppress, mostly.

So it's likely you'd need a preselector to drive down the unwanted
overloading signals; possibly you'll hear more then on the frequency
you're tuned to.

Alternatively your outdoor antenna can be a low noise one, and give
you an advantage you don't get indoors. Ie. designed not to pick
up signals and noise you don't want to hear. Whether this is dimmer
noise from neighbors or power pole insulators breaking down, or
some local broadcaster, depends on your situation.

I use active antennas outdoors and phase them to produce nulls,
chiefly on MW. Nulling SW signals that are not locally produced
is difficult by phasing though, unless you have a huge number of
elements to produce an extended null.

A passive pre-selector is almost mandatory when using a good external
antenna with a sensitive portable like the SW77. I had to do this with
my '2010'. Otherwise the bands were full of spurious signals
(intermod's).


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